256 research outputs found
To pup or not to pup? Using physiology and dive behavior to answer the Weddell Seal's overwinter question
Thesis (Ph.D.) University of Alaska Fairbanks, 2015Female Weddell seals (Leptonychotes weddellii) haul-out on the fast-ice surrounding the Antarctic continent in October and November each year to give birth to and nurse their pups. Breeding follows directly after weaning (December) and the annual molt begins in January-February. Animals reduce foraging efforts during the lactation and molting periods, but very little is known regarding the influence of this reduced activity on physiological condition. After a period of embryonic diapause, the annual molt coincides with embryo attachment and the start of active gestation. Consequently, female physiological condition at this time may influence reproductive success the following year. Overall female health and the ability to forage successfully throughout the gestation period (austral winter) may impact the likelihood that a pregnancy is brought to term. Therefore, this study tested whether overwinter changes in Weddell seal physiology and foraging efforts are reflected in reproductive outcomes the following year (i.e., to answer the over winter question of "to pup or not to pup?"). From 2010-2012, 100 (January-February: n = 53; October-November: n = 47) adult female Weddell seals were captured in Erebus Bay, Antarctica to assess overwinter changes in physiological condition and/or dive behavior that may be associated with reproductive success. Morphometric measurements and isotopic dilution procedures revealed that female Weddell seals gain ~10-15% of their body mass across the winter period, primarily in the form of blubber and lipid mass. The proportion of mass and lipid gain was similar regardless of whether females returned the following year and successfully gave birth, or did not produce a pup. Further, the amount of mass and energy acquired across gestation in the Weddell seal was markedly less than previously reported for other phocid species. Despite changes in activity patterns and body composition, Weddell seals maintained blood hemoglobin and muscle myoglobin concentrations across the winter. Therefore, Weddell seal total body oxygen stores and calculated aerobic dive limit (cADL) were conserved. This ensures that females have the physiological capabilities to effectively forage directly following the annual molt when they are at their leanest and must regain body mass and lipid stores. Although aerobic capacities did not change, dive effort varied considerably throughout the austral winter. Proxies of dive effort (duration, depth, %dives > cADL) were highest just after the molt (January-February) and just prior to the subsequent pupping season (August-September). Additionally, the proportion of each day spent diving increased mid-winter. Females that were observed the following year with a pup significantly increased all indices of foraging effort during the austral winter as compared to females that returned without a pup. This study is the first to identify and measure differences in dive efforts due to reproductive status, and indicates that successful reproduction is associated with greater foraging effort
Manajemen Pembelajaran Berbasis Karakter di Sekolah Dasar Islam Terpadu (SDIT)
Krisis karakter telah menjadi permasalahan yang kompleks dan multidimensial. Sekolah dengan sistem full day school dapat dijadikan solusi untuk mengatasi hal tersebut, serta manajemen pendidikan melalui pelaksanaan empat fungsi dasar planning, organizing, actuating dan controlling yang sudah tertata dengan baik akan dapat mendukung pendidikan karakter sebagai dasar pembentuk siswa yang berakhlak. Penelitian ini dilakukan di Sekolah Dasar Islam Terpadu (SDIT) Luqman Al Hakim yang bertujuan untuk mengungkapkan fenomena yang terjadi kaitannya dengan manajemen pembelajaran berbasis karakter di sekolah dasar Islam terpadu.
Penelitian ini merupakan penelitian kualitatif yaitu penelitian yang berusaha mendeskripsikan suatu gejala, peristiwa, kejadian yang terjadi pada saat sekarang atau saat penelitian dilaksanakan, dengan menghimpun data atau informasi sebanyak-banyaknya untuk menemukan teori dari dasar, bersifat deskriptif, lebih mementingkan proses dari pada hasil. Data dikumpulkan dengan instrumen pengumpulan data berupa lembar observasi dan lembar wawancara terhadap 1 orang kepala sekolah, 4 kepala divisi, 2 orang guru, dan 2 orang tua siswa. Setelah dikumpulkan, data kemudian dianalisis dengan menggunakan tehnik anĂĄlisis kualitatif, yang meliputi kegiatan (1) mereduksi data (proses menyeleksi, memfokuskan dan menyederhanakan semua data mentah dan kasar yang diperoleh), (2) menyajikan data secara naratif ataupun matriks, dan (3) menarik kesimpulan serta verifikasi terhadap hasil penafsiran dan evaluasi.
Hasil penelitian menunjukkan: 1) SDIT Luqman Al Hakim sudah menerapkan manajemen pembelajaran berbasis karakter secara optimal, berdasarkan dari tahap pelaksanaan POAC (planning, organizing, actuating, dan controlling) yang berkesinambungan dan komprehensif dalam mewujudkan pembelajaran berbasis karakter. 2) Pembelajaran berbasis karakter yang bersumber dari nilai-nilai akhlak seperti akhlak terhadap tuhan (khalik), akhlak terhadap sesama manusia, akhlak terhadap lingkungan dapat di implementasikan oleh SDIT Luqman Al Hakim yang terwujud dari berbagai program kegiatan sekolah yang dikembangkan. 3) Manajemen pembelajaran berbasis karakter di SDIT Luqman Al Hakim memiliki faktor pendukung dan penghambat dalam penerapannya seperti pengelolaan SDM, implementasi kurikulum, pengelolaan sarana prasarana dan hubungan antar pihak internal dan eksternal
In vitro and in vivo modification of Neisseria gonorrhoeae lipooligosaccharide epitope structure by sialylation.
After growth of gonococci in the presence of cytidine monophospho-N-acetyl-neuraminic acid (CMP-NANA), their 4.5-kD lipooligosaccharide (LOS) component was increased by approximately 400 daltons, whereas the LOS of strains lacking the 4.5-kD component were unaffected. Expression of mAb-defined epitopes on the 4.5-kD component was decreased on LOS of strains grown in CMP-NANA, and treatment of the LOS with neuraminidase reversed this affect. Gonococci incubated with human PMNs also had decreased expression of the 4.5-kD+ epitopes. A detergent extract of gonococci incorporated radiolabeled NANA in the LOS, suggesting the presence of a sialyltransferase in gonococci. Exogenous sialyltransferases also could use LOS as an acceptor
Temporal changes in Weddell seal dive behavior over winter: are females increasing foraging effort to support gestation?
© The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ecology and Evolution, 8(23), (2018): 11857-11874. doi: 10.1002/ece3.4643.In capitalâbreeding marine mammals, prey acquisition during the foraging trip coinciding with gestation must provide energy to meet the immediate needs of the growing fetus and also a store to meet the subsequent demands of lactation. Weddell seals (Leptonychotes weddellii) that give birth following the gestational (winter) foraging period gain similar proportions of mass and lipid as compared to females that fail to give birth. Therefore, any changes in foraging behavior can be attributed to gestational costs. To investigate differences in foraging effort associated with successful reproduction, twentyâthree satellite tags were deployed on postâmolt female Weddell seals in the Ross Sea. Of the 20 females that returned to the area the following year, 12 females gave birth and eight did not. Females that gave birth the following year began the winter foraging period with significantly longer and deeper dives, as compared to nonâreproductive seals. Midâ to late winter, reproductive females spent a significantly greater proportion of the day diving, and either depressed their diving metabolic rates (DMR), or exceeded their calculated aerobic dive limit (cADL) more frequently than females that returned without a pup. Moreover, nonâreproductive females organized their dives into 2â3 short bouts per day on average (BOUTshort; 7.06 ± 1.29 hr; mean ± 95% CI), whereas reproductive females made 1â2 BOUTshort per day (10.9 ± 2.84 hr), comprising one long daily foraging bout without rest. The magnitude of the increase in dive activity budgets and depression in calculated DMR closely matched the estimated energetic requirements of supporting a fetus. This study is one of the first to identify increases in foraging effort that are associated with successful reproduction in a top predator and indicates that reproductive females must operate closer to their physiological limits to support gestational costs.We are grateful for the help of field team members: Drs. Luis HĂŒckstĂ€dt, Linnea Pearson, and Patrick Robinson for sample collection. Group Bâ009âM led by Drs. Robert Garrott, Jay Rotella, and Thierry Chambert provided information regarding animal reproductive status and provided great assistance in locating study animals. Logistical support was provided by the National Science Foundation (NSF) U.S. Antarctic Program, Raytheon Polar Services, and Lockheed Martin ASC; we thank all the support staff in Christchurch, NZ and McMurdo Station. This research was conducted with support from NSF ANTâ0838892 to D.P.C. and ANTâ0838937 to J.M.B. For J.M.B., this material is based upon work while serving at the National Science Foundation, and M.R.S was supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGEâ1242789. Any opinion, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. Animal handling protocols were approved by the University of Alaska Anchorage and University of California Santa Cruz's Institutional Animal Care and Use Committees. Research and sample import to the United States were authorized under the Marine Mammal permit No. 87â1851â04 issued by the Office of Protected Resources, National Marine Fisheries Service. Research activities were also approved through Antarctic Conservation Act permits while at McMurdo Station
Iron mobilization during lactation reduces oxygen stores in a diving mammal
© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Shero, M. R., Kirkham, A. L., Costa, D. P., & Burns, J. M. Iron mobilization during lactation reduces oxygen stores in a diving mammal. Nature Communications, 13(1), (2022): 4322, https://doi.org/10.1038/s41467-022-31863-7.The profound impacts that maternal provisioning of finite energy resources has on offspring survival have been extensively studied across mammals. This study shows that in addition to calories, high hemoprotein concentrations in diving mammals necessitates exceptional female-to-pup iron transfer. Numerous indices of iron mobilization (ferritin, serum iron, total-iron-binding-capacity, transferrin saturation) were significantly elevated during lactation in adult female Weddell seals (Leptonychotes weddellii), but not in skip-breeders. Iron was mobilized from endogenous stores for incorporation into the Weddell sealâs milk at concentrations up to 100Ă higher than terrestrial mammals. Such high rates of iron offload to offspring drew from the femaleâs own heme stores and led to compromised physiologic dive capacities (hemoglobin, myoglobin, and total body oxygen stores) after weaning their pups, which was further reflected in shorter dive durations. We demonstrate that lactational iron transfer shapes physiologic dive thresholds, identifying a cost of reproduction to a marine mammal.This research was conducted with support from NSF ANT-0838892 to DPC; ANT-0838937 and ANT-1246463 to JMB (which also supported ALK and MRS); and The Investment in Science Fund at WHOI to MRS
Sensitive aerial hearing within a noisy nesting soundscape in a deep-diving seabird, the common murre Uria aalge
Diving seabirds face a combination of sound exposure in marine and terrestrial environments due to increasing human encroachment on coastal ecosystems. Yet the sound-sensitivity and sensory ecology of this threatened group of animals is largely unknown, complicating effective management and conservation. Here, we characterize aspects of the acoustic ecology of the common murre Uria aalge, one of the deepest diving alcid seabirds. Electrophysiological aerial hearing thresholds were measured for 12 wild, nesting individuals and compared to conspecific vocalizations and short-term aerial soundscape dynamics of their cliff nesting habitat. Auditory responses were measured from 0.5 to 6 kHz, with a lowest mean threshold of 30 dB at 2 kHz and generally sensitive hearing from 1 to 3.5 kHz. The short-term murre nesting soundscape contained biotic sounds from con- and heterospecific avifauna; broadband sounds levels of 56-69 dB re: 20 ”Pa rms (0.1-10 kHz) were associated with both diel and tidal-cycle factors. Five murre vocalization types showed dominant spectral emphasis at or below the region of best hearing. Common murre hearing appears to be less sensitive than a related alcid, the Atlantic puffin Fratercula arctica, but more sensitive than other non-alcid diving birds described to date, suggesting that adaptations for deep diving have not caused a loss of the speciesâ hearing ability above water. Overall, frequencies of common murre hearing and vocalization overlap with many anthropogenic noise sources, indicating that the species is susceptible to disturbance from a range of noise types
Seasonal Habitat Preference and Foraging Behaviour of Post-Moult Weddell Seals in the Western Ross Sea
Weddell seals (Leptonychotes weddellii) are important predators in the Southern Ocean and are among the best-studied pinnipeds on Earth, yet much still needs to be learned about their year-round movements and foraging behaviour. Using biologgers, we tagged 62 post-moult Weddell seals in McMurdo Sound and vicinity between 2010 and 2012. Generalized additive mixed models were used to (i) explain and predict the probability of seal presence and foraging behaviour from eight environmental variables, and (ii) examine foraging behaviour in relation to dive metrics. Foraging probability was highest in winter and lowest in summer, and foraging occurred mostly in the water column or just above the bottom; across all seasons, seals preferentially exploited the shallow banks and deeper troughs of the Ross Sea, the latter providing a pathway for Circumpolar Deep Water to flow onto the shelf. In addition, the probability of Weddell seal occurrence and foraging increased with increasing bathymetric slope and where water depth was typically less than 600 m. Although the probability of occurrence was higher closer to the shelf break, foraging was higher in areas closer to shore and over banks. This study highlights the importance of overwinter foraging for recouping body mass lost during the previous summer
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